The Mass Distribution of the Most Luminous X-Ray Cluster RXJ 1347.5-1145 From Gravitational Lensing

Galaxy cluster mass distribution are potentially useful probes of $Omega_0$ and the nature of the dark matter. Large clusters will distort the observed shapes of background galaxies through gravitational lensing allowing the measurement of the cluster mass distributions. In this paper we describe weak statistical lensing measurements of the most luminous X-ray cluster known, RXJ1347.5-1145 at z=0.45. We detect a shear signal in the background galaxies at a signal-to-noise ratio of 7.5 in the radial range $120 le r le 1360 h^{-1}$ kpc. A mass map of the cluster reveals an 11$sigma$ peak in the cluster mass distribution consistent with the position of the central dominant galaxy and 3 $sigma$ evidence for the presence of a subcluster at a projected radius of 1.3 - 1.7 h^{-1} Mpc from the cluster center. In the range $120 le r le 1360 h^{-1}$ kpc mass traces light, and the azimuthally averaged cluster mass and light profiles are consistent with singular isothermal spheres with M(r<1 Mpc) = $1.7 pm 0.4 imes 10^{15} M_odot$. Assuming an isotropic velocity distribution function, the implied velocity dispersion is $sigma = 1500 pm 160 km s^{-1}$. The rest-frame mass-to-light ratio is $M/L_B = 200 high as a previously determined X-ray mass estimate